Prefix with chamber (4)
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">prefix with chamber</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for ante that I've seen before include "A neat sort of prefix" , "Stake; before (Lat.)" , "Poker-player's stake before the deal" , "Stake (that may be upped?)" , "Money for poker" .)